diff --git a/backend/app/controllers/tag_descriptions_controller.rb b/backend/app/controllers/tag_descriptions_controller.rb
index de2685d..52859ac 100644
--- a/backend/app/controllers/tag_descriptions_controller.rb
+++ b/backend/app/controllers/tag_descriptions_controller.rb
@@ -48,9 +48,8 @@ class TagDescriptionsController < ApplicationController
     description = TagDescription.find_by(tag_id: params[:id], language_code: 'ja')
     return head :not_found unless description
 
-    page = WikiPage.find(description.id)
     TagDescriptionOperation.update!(
-        description:, page:, body:, updated_by_user: current_user)
+        tag: description.tag, body:, updated_by_user: current_user)
     description.reload
 
     render json: representation(description)
diff --git a/backend/app/services/tag_description_operation.rb b/backend/app/services/tag_description_operation.rb
index 342cefb..c6568de 100644
--- a/backend/app/services/tag_description_operation.rb
+++ b/backend/app/services/tag_description_operation.rb
@@ -7,7 +7,7 @@ class TagDescriptionOperation
       raise ActiveRecord::RecordNotUnique if TagDescription.exists?(
           tag_id: tag.id, language_code: LANGUAGE_CODE)
 
-      page = Wiki::Commit.create_legacy_content!(
+      page = Wiki::CompatibilityWriter.create!(
           tag_name: tag.tag_name(LANGUAGE_CODE), body:, created_by_user:, message:)
       revision = page.wiki_revisions.order(id: :desc).first
       record_version!(tag:, revision:, body:, user: created_by_user,
@@ -16,18 +16,23 @@ class TagDescriptionOperation
     end
   end
 
-  def self.update!(description:, page:, body:, updated_by_user:, message: nil,
+  def self.update!(tag:, body:, updated_by_user:, message: nil,
                    base_revision_id: nil)
     ApplicationRecord.transaction do
+      tag.lock!
+      description = TagDescription.lock.find_by(
+          tag_id: tag.id, language_code: LANGUAGE_CODE)
       description&.lock!
-      page.lock!
-      revision = Wiki::Commit.legacy_content!(
-          page:, body:, created_user: updated_by_user, message:,
+      tag_name = tag.tag_name(LANGUAGE_CODE)
+      page = WikiPage.lock.find_by!(tag_name:)
+      revision = Wiki::CompatibilityWriter.update!(
+          page:, body:, updated_by_user:, message:,
           base_revision_id:)
-      record_version!(tag: page.tag_name.tag, revision:, body: revision.body,
+      next unless revision
+
+      record_version!(tag:, revision:, body: revision.body,
                       user: updated_by_user, description:)
-      description || TagDescription.find_by!(
-          tag_id: page.tag_name.tag_id, language_code: LANGUAGE_CODE)
+      revision
     end
   end
 
diff --git a/backend/app/services/wiki/commit.rb b/backend/app/services/wiki/commit.rb
index 80913f1..e1c37a5 100644
--- a/backend/app/services/wiki/commit.rb
+++ b/backend/app/services/wiki/commit.rb
@@ -43,11 +43,9 @@ module Wiki
 
     def self.content! page:, body:, created_user:, message: nil, base_revision_id: nil
       tag = page.tag_name.tag
-      description = tag && page.tag_name.language_code == 'ja' &&
-          TagDescription.find_by(tag_id: tag.id, language_code: 'ja')
       if tag && page.tag_name.language_code == 'ja'
         return TagDescriptionOperation.update!(
-            description:, page:, body:, updated_by_user: created_user,
+            tag:, body:, updated_by_user: created_user,
             message:, base_revision_id:)
       end
 
diff --git a/backend/app/services/wiki/compatibility_writer.rb b/backend/app/services/wiki/compatibility_writer.rb
new file mode 100644
index 0000000..2bb003c
--- /dev/null
+++ b/backend/app/services/wiki/compatibility_writer.rb
@@ -0,0 +1,33 @@
+module Wiki
+  class CompatibilityWriter
+    def self.create! tag_name:, body:, created_by_user:, message: nil
+      Commit.create_legacy_content!(
+          tag_name:, body:, created_by_user:, message:)
+    end
+
+    def self.update! page:, body:, updated_by_user:, message: nil,
+                     base_revision_id: nil
+      normalised = Commit.normalise_body(body)
+      if normalised.blank?
+        return Commit.legacy_content!(
+            page:, body: normalised, created_user: updated_by_user, message:,
+            base_revision_id:)
+      end
+
+      if base_revision_id.present?
+        current_id = page.wiki_revisions.maximum(:id)
+        if current_id && current_id != base_revision_id.to_i
+          raise Commit::Conflict,
+              "競合が発生してゐます" +
+              "（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
+        end
+      end
+
+      return if Commit.normalise_body(page.body) == normalised
+
+      Commit.legacy_content!(
+          page:, body: normalised, created_user: updated_by_user, message:,
+          base_revision_id:)
+    end
+  end
+end